At international level, the WHO formulated guidelines for the treatment of severe acute malnutrition (or wasting) (WHO 1999, and more recently ACF 2011), and guidelines for moderate acute malnutrition (or wasting) are in the process of formulation. In contrast, surprisingly little is known on preventive schemes for acute malnutrition. In Haiti, Ruel et al (2008) found that targeting nutrition interventions to prevent children from becoming malnourished might be more effective than curative treatment to reduce child wasting. In addition, recent preventive trials in humanitarian settings focused on the use of food-based strategies, especially ready-to-use food (Isanaka, 2009; Hendricks, 2010; Parikh, 2010; Imbad, 2011). However, it is well known that the causes of under-nutrition are numerous and also relate to inadequate health and care practices, lack of food diversification, food insecurity... Therefore, the MAM'Out research project aims at assessing context-adapted sustainable preventive approaches, not based primarily on food supplementation. The objective is to provide an evidence base for these alternative approaches, in order that proven interventions be taken into account for scale-up at policy-making levels. More specifically, the MAM'Out project aims at evaluating two innovative approaches to prevent acute malnutrition, in terms of effectiveness and cost-effectiveness in the Tapoa province (East region of Burkina Faso, Africa). These preventive approaches have been identified as relevant to implement in this specific context.. Firstly, we propose to test a family development strategy (FD), a child-centered educational and home-based intervention aiming at mitigating the global family context of households vulnerable to under-nutrition. The objective is to counsel families with children under 2 to find the most advisable solutions to improve their living conditions and to acquire best possible behaviors to prevent acute malnutrition. Key messages will vary according to children age and will encompass issues with nutritional education, care practices, health, child development and hygiene. The second approach consists of a seasonal and multi-annual cash transfer (CT) program in the framework of a safety net, targeted to economically and nutritionally vulnerable households with children less than 2 years old. In order to fully adapt ths intervention to the Sahel households' context, a deeper analysis of the causes of under-nutrition will be made prior to the intervention. This will allow deciding whether it is relevant or not to condition CTs and which criteria is the most appropriate for CT conditioning. This study will be designed as a three-arm cluster randomized intervention trial, based on randomization of triple-matched rural villages of the Tapoa province. Two arms will receive the intervention and one will be a control arm. The main outcome will be the incidence of acute malnutrition (or wasting). Anthropometric measures (height, weight, edema and MUAC) will be measured at home, as well as indicators of diet diversity, hemoglobin, child development and morbidities. Questionnaires and 24-hour food recalls will also be analyzed, and a cost-effectiveness ratio will be calculated. This project is proposed by Action Contre la Faim - France, a non-governmental non-for- profit organization, and supported through a multi-annual formalized collaboration by two research institutions: Gent University (Belgium) and AgroParisTech University (France). The total length of the project is 3.5 years, with 2 years of direct interventions and measurements in the field.